The invention relates to a monolithically integrated transformer, in particular a high-frequency transformer with the highest possible coupling factor.
A transformer of this type is disclosed in U.S. Pat. No. 4,816,784, in which the conductor tracks of the winding and crossovers are disposed in such a way that conductor tracks located beside one another belong to different windings, in order to achieve a particularly good magnetic coupling.
It is accordingly an object of the invention to provide a monolithically integrated transformer that overcomes the above-mentioned disadvantages of the prior art devices of this general type, which has a smaller number of secondary windings than primary windings and which, utilizing three possible metallization planes of conventional silicon bipolar semiconductor technology, has a particularly high coupling factor.
With the foregoing and other objects in view there is provided, in accordance with the invention, a monolithically integrated transformer. The transformer contains a primary winding having conductor tracks, and a secondary winding having conductor tracks. The secondary winding has slots formed therein such that the conductor tracks of the secondary winding are connected in parallel, in which, between the conductor tracks of the secondary winding connected in parallel, at least parts of the primary winding are present.
The essential idea of the present invention is to provide windings with slots and to connect conductor tracks belonging to the winding in parallel and, between these parallel-connected conductor tracks, to dispose the conductor tracks of another winding. In this case, the other winding can, for example, also be slotted in a corresponding manner.
In accordance with an added feature of the invention, both the primary winding and the secondary winding have connecting regions and crossing regions. The conductor tracks of the primary winding and the secondary winding are substantially concentrically disposed circular segment-shaped conductor tracks.
In accordance with an additional feature of the invention, the conductor tracks of the primary winding and the secondary winding each have a cross section increasing linearly in a radial direction.
In accordance with a further feature of the invention, the primary winding and the secondary winding are formed from three metallization layers. The primary winding, apart from the connecting regions and the crossing regions, extends completely over two of the three metallization layers. The secondary winding, apart from the connecting regions and the crossing regions, extends completely over the three metallization layers.
In accordance with a further added feature of the invention, the primary winding has a tap, a first primary winding part and a second primary winding part connected to each other through the tap, and in a radial direction, the conductor tracks of the first primary winding part alternate with conductor tracks of the second primary winding part and, in their projection, run in mirror image fashion on a common plane.
With the foregoing and other objects in view there is further provided, in accordance with the invention, a monolithically integrated transformer. The transformer contains a secondary winding having conductor tracks, and a primary winding having conductor tracks. The primary winding has slots formed therein such that the conductor tracks of the primary winding are connected in parallel, in which, between the conductor tracks of the primary winding connected in parallel, at least parts of the secondary winding are present.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a monolithically integrated transformer, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.